This project encompasses all statistical coordinating center responsibilities for collaborative clinical studies undertaken by this Section. Currently the major collaborative clinical study being planned is a double-blind trial designed to examine the influence of anticonvulsant therapy on the natural history of seizure disorders in young patients. Whether treatment after the first seizure can alter likelihood of development of chronic epilepsy Is a question often raised with no definitive answer. A number of observational studies establish that many persons who experience a first generalized convulsion do not experience a recurrence during two to five year periods of follow-up. Since prescription of anticonvulsant medication involves risk of side effects as well as expense, it might be desirable to withhold a commitment to chronic therapy until a second or subsequent seizure takes place. On the other hand, there has been anxiety that any seizure makes a subsequent recurrence more likely, and that early therapy might prevent the development of chronic epilepsy. For the resolution of these important questions, there is a need for a study that enrolls patients very soon following an initial nonfebrile seizure, decides by random assignment whether to treat with antiepileptic medication or placebo, follows subjects for compliance and subsequent clinical history, and arrives at a judgment as to which arm of the study has fared better with regard to both seizure recurrence, and toxicity. A second collaborative study being planned is a follow-up study of survivors of neonatal respiratory dysfunction treated by Extracorporeal Membrane Oxygenation (ECMO) and a control group. The long-term, i.e. 5-7 year, neurologic, motor and psychologic effects of ECMO will be compared with that of the control group. A consortium of medical centers which have been performing ECMO since the early 1980s will provide both the ECMO-treated patients and the controls.